Excellent advice above from our pal
@thatguyoverthere440
Stiff racquets can often be surprisingly comfortable players when strung with soft strings. Natural gut has worked miracles for some players in the past who can't get along with anything else. It retains its resilience and performance right up until it breaks, but it's more expensive than anything else.
On the other hand, a soft racquet with an especially arm-friendly reputation can become much more harsh when paired with a stiff string like a full bed of poly, even if it's tensioned rather low.
***Just spotted your new post. Good to see that you're trying a multifiber. It's also great that you're up for sampling a set of natural gut. I've been stringing at home for perhaps fifteen years and I've never tried that string myself so far. Its relatively high cost has probably steered me toward less expensive options that are kind to my arm.***
If you're not used to the weight and balance of a different racquet, it might be difficult to consistently find the sweet-spot while you're using it, even if the head size is a little bit larger than your regular frame. I used an older 95" ProStaff for several years - not the same model as yours - and not many racquets today are very similar to those older ones.
The move that worked for me when I switched to more current frames from my Wilsons was a couple of the softer and heavier models from Volkl. I have their C10, older Organix 10 (325g version), and also their more recent V-Sense 10 325g. All of these have 98" heads and have been very good for me in different roles - teaching, coaching high school teams, and playing on my own. I've been fine with the 98" frames, but this seems to be the upper limit in terms of my own preference.
I also get enough comfort from my racquets when I string them with synthetic gut. This string type can offer moderate softness and I generally like the "crisp" feel and control I get with it compared with what I usually find in a multifiber. I blew up my arm with a serious case of tennis elbow after trying a full bed of poly about two years ago, so I'm also avoiding harsh strings as a rule.
Multifiber can be great, but whenever I try a set, it tends to soften and degrade too quickly for me to be useful for more than a few outings. Syn. gut seems to retain a little more backbone for me as I use it and I usually can play my syn. gut up until it snaps. If the softness of multifiber is too soft for you, a syn. gut at moderate tension could be an alternative that is also rather easy on your arm. But for now, I think you're making the smartest first move by switching to substantially softer string.
