Having just turned 60, I'm relatively old-school in terms of the roots of my game - playing with a wood racquet until half way through high school - but I've been coaching for over 20 years, stringing for most of that time, and making lots of observations with equipment trends along the way. A couple considerations:
It might be beneficial for you to measure the static weight and balance of your two models - the EZone 100 and VCore 98. Since the 100 isn't forcing you to use extra grip pressure, it sounds like that one has the better layout - the better "fit" for your technique. Even though the 98 should have some theoretical control advantages based on its specs, it's not giving you practical advantages in action on the court. You absolutely should not need to be using extra grip pressure or a more active forearm to steer your racquet to the ball. Big red flag there.
The 98 might have less head-light (HL) balance than the 100 or it might have the same balance, but also a higher static weight. In either case, that will probably make the 98 feel slower and trick you into using more grip action to work the racquet to the ball compared with the 100. That can be tweaked into a better layout with some home tuning using a couple of packs of cheap lead tape (1/4" for the hoop and 1/2" for the handle). There are lots of threads about tuning our own equipment here and TW probably has some info about this in their Learning Center, etc.
But regardless of the stock specs of the 98 or whatever tweaks you may be able to do with it, that frame might just be a bad fit for you. The simple combo of the static weight, balance, and flex of the 100 is probably a good template for what's more or less right for you.
I'll also point out that grip sizes have trended much smaller these days. That's a tradeoff, not a universal benefit. A smaller grip might feel easier to whip through the ball, but it can be much more difficult to stabilize the racquet through contact without using extra grip pressure. Smaller grips don't work for everybody.
Very much agree with our pal
@ohplease in post #10. If you're mending some elbow pain, my experience has convinced me that the easiest and most effective first step that you can take to help with that is to get off the poly strings for a little while. Don't think about switching to a more arm-friendly racquet right away. Anytime we switch to a different racquet that's unfamiliar, we're going to rack up more mis-hits with it until we get used to it. That adjustment period alone is often a little rough on the arm. If the 100 doesn't hurt you, use that one.
Even though softer strings are typically less durable than poly, many are also rather affordable. I recommend softer syn. guts around here all the time (Gosen OG Sheep Micro and Prince SG with Duraflex are too stiff for my taste). They generally outperform most multis, they're much more affordable than premium multis like NXT and Biphase, and they offer moderate softness that can be much more arm-friendly than many poly options. If you want to try a multi that should give you decent service life along with the inherent softness of a multi string, I recommend sampling one or two sets of Prince Premier Control in the heavier 15L gauge. I've used this to help a few young sluggers I've coached who were playing through some soreness in the middle of a competitive season. It lasts nearly twice as long as the 16 ga. and it seemed to reverse the onset of tennis elbow for one kid and just about cure a nasty case of golfer's elbow for another after switching into it.
