Several elements will play in your favor here and you will likely have no trouble getting the room you need.
1- June is not high
DVC season, as point costs are higher, and will not be in high demand.
2- You want a 1BR which is a booking category that tends book up well into the 7 month window in June because of the low “value” proposition (sleeps same as studio at more than twice the points in some cases - like CCV in mid-June)
3- There are likely to be a couple more declarations (if not the balance of held units) by then so there is likely to be increased availability.
4- This is between 4 and 6 months before the scheduled opening of SWGE and a lot of once-in-a-life-timers may wait until the next summer to make their trek to WDW (rental demand lower than once SWGE open).
5- The average temp in Central Florida in June is 218F/103 C (found on Wikipedia). Public buildings shut down and citizens are ordered to shelter in place as to avoid people’s faces melting off their heads, so a lot of sane DVCers (who’s points stop working above 85F) avoid walking around for six hours under the face-melting sun just to watch their Mickey bars vaporize before it reaches their lips.
So yeah, book your home resort, modify at 7-months. You
should be* fine.
ETA: *Who knows if they suddenly announce a MM event during your stay (for all he reasons listed above) which would throw a wrench in your plans, so do book your home resort as a backup.