Shocks for 78 KZ1000 LTD

I am looking for something to replaced the saggy OEM shocks on my LTD. I was looking at Progressives, but the 12-series look like they may be too fat at the bottom and may foul the chainguard.

I want something 13.5" and with a heavier than standard spring. Progressive also makes a 14-series, which is skinnier at the bottom and might fit better. Anyone used either?

I had the 12 series on one of my bigger Hondas a year ago . I was very happy with them ,, the bike only had 12,000 miles on it but the shocks had become soft .. Really made a big change in the way the rode and handled