Evening All,
I’m a single speed luddite at heart and can count on one hand the number of full suspension bikes I’ve had.
My current full squish bike is a thoroughly unfashionable, but I like it, Orange Gyro 29er.
I’m tempted to try some offset shock bushes to lower the hightower nature of the BB.
Are there any downsides to using them - I’m thinking of trying a pair. They should slacken the HT and ST by a degree and lower the BB by 10mm.
Cheers,
Mark 
I'd look at using an angle adjust head set instead as it doesn't have the downside of slackening the seat tube.
I’ve been using www.offsetbushings.comfor years with no problems. I’ve had them on an Alpine 160 and a Five over the years. I’ve used Burgtec Ti ones before as well but they weren’t any better
I’d also recommend fitting a -2 angleset as well.
The Fair Cycle drop best are brilliant for older bikes with a slacker seat angle, so if you go for offset bushings (they work well), then you might want to consider one of these. I’ve got one, and although quite expensive, it meant I didn’t need to sell a frame.
https://www.fairbicycle.com/product-page/drop-best-uc-m6
They do different types depending on your seat post, so have a gander around their web page.