Again though, realistically we are brimming with SFs at the moment, in fact overflowing the 48min available. While on the other hand we've got a still muddled PF spot. And with WCS as a 4/5, there's an opportunity for a Skal to turn it into a two-skinny boys and one big boy Cuz/Skal/WCS frontcourt.
The skinnyness thing we'll just have to see. It has been accurately noted that the golden era of the PFs is past -- in fact the current junkball fad has really declared war more on PFs than it has on Cs. Almost every team still has one or more big bodies Cs on the roster, and Skal absolutely cannot play them without getting broken like a matchstick. But the PFs have been heavily eroded and junkified, and when teams throw out random Ilyasova/Morris twin level crap at the position, I doubt Skal is going to be truly physically overwhelmed. There will be bad matchup nights (Favors, Zach etc.) , but he can play a lot more 4s today than he could have 15-20 years ago. And unlike the non-PF blown up SFs, he's got the length to help defend inside even if his man is a beast.
As for the rest, if he's going to swing either way, either 4/5 or 4/3 then I would say 4/3. The 5s just do not look practical, and frankly that may have been a part of Cal's mistake at Kentucky. Skal is just too skinny/wussy to do anything against even 2nd and 3rd tier guys like a Zaza Pachulia, and big guys with game like Valanciunas would chew him up. On the other hand, with that frame, ballhandling, range on his shot, and length, there could be some Tayshaun Prince ype SF minutes against the right matchups. SF play though depends on having lateral quickness, and we would need more evidence, which may not come in spades in a year with Rudy/Omri and Barnes all here.